1. Field of the Invention
The present invention refers to compounds of a peptide nature which show the capability to influence the immune response in mammals.
The polypeptide compounds are identified by the following sequence of aminoacids: EQU A--X--B
in which
A indicates PYR, PRO, Z-PRO PA1 B indicates TRP, PHE, TYR, and PA1 X indicates GLY, VAL, GLU, ASP, SER, ALA, ASN, GLN, ILE, LEU, PRO, LYS and ARG.
The above mentioned compounds, along with their salts and esters, show an immunostimulant or immunodepressant activity, and can therefore be used generally in therapy as immunomodulators.
2. Description of the Prior Art
The above compounds are made up in the first place of a tripeptide structure PYR-X-TRP, in which X has the meaning indicated above, which represents tripeptide compounds already known from EP-B-0148133 and Italian patent 1186733.
According to the present invention it has been found that said tripeptide compounds also show activity as immunomodulating agents.
In the above mentioned patents these tripeptide compounds were evaluated as anti-hypertension or analgesic agents.
It is further known from conventional medicine that snake poisons have the property of stimulating the immune response of the animals and humans bitten. This feature, which is used to the present day for the preparation of vaccines permitting the reduction of damage caused by poisoning, is generally attributed to the fact that in snake poisons are present antigen patterns, capable of stimulating specific and aspecific responses within the immunitary system of the poisoned animal. As regards the specific responses, snake poisons contain numerous toxins which stimulate the production of clearly distinguishable antibodies.